There has been known a deficiency inspecting device for a sheet-shaped product including an optical film (Patent Literature 1). The deficiency inspecting device receives information on a deficiency from a protective film inspecting section, and forms a data code (for example, a two-dimensional code or a QR Code [registered trademark]) having a fixed pitch and indicative of the deficiency. The deficiency inspecting device forms such a data code on a surface at an end of a PVA film original sheet together with information on the position and production identification.
Further, there has been known a defect indicating method for specifying a defective portion of a sheet of paper, the method including cutting a sheet of paper to divide it into a plurality of narrower sheets of paper and providing a visible indicator at a portion corresponding to a defect in a sheet of paper as divided (see Patent Literature 2).